Within-Subject Variability and the Influence of Exercise Training History on the Resting Plasma Metabolome in Men

Abstract

This study investigated within-subject variability in the circulating metabolome under controlled conditions, and whether divergent exercise training backgrounds were associated with alterations in the circulating metabolome assessed in resting samples. Thirty-seven men comprising of endurance athletes (END; body mass, 71.0 ± 6.8 kg; fat-free mass index, 16.9 ± 1.1 kg/m2), strength athletes (STR; 94.5 ± 8.8 kg; 23.0 ± 1.8 kg/m2), and recreationally active controls (CON; 77.6 ± 7.7 kg; 18.1 ± 1.0 kg/m2) provided blood samples after an overnight fast on two separate occasions controlled for time of day of sampling, recent dietary intake, time since last meal, and time since last exercise training session. A targeted profile of metabolites, performed using liquid chromatography and mass spectrometry on plasma samples, identified 166 individual metabolites and metabolite features, which were analyzed with intraclass correlation coefficients, a multilevel principal component analysis, and univariate t tests adjusted for multiple comparisons. The median intraclass correlation coefficient was .49, with 46 metabolites displaying good reliability and 31 metabolites displaying excellent reliability. No difference in the abundance of any individual metabolite was identified within groups when compared between visits, but a combined total of 44 metabolites were significantly different (false discovery rate <0.05) between groups (END vs. CON, 42 metabolites; STR vs. CON, 10 metabolites; and END vs. STR, five metabolites). Under similar measurement conditions, the reliability of resting plasma metabolite concentrations varies largely at the level of individual metabolites with ∼48% of metabolites displaying good-to-excellent reliability. However, a history of exercise training was associated with alterations in the abundance of ∼28% of metabolites in the targeted profile employed in this study.

The separation and identification of circulating small extracellular vesicles from endurance‐trained, strength‐trained and recreationally active men

“…Male participants ( n = 38) who were recreationally active controls (CON; n = 12), endurance‐trained (END; n = 13) or strength‐trained (STR; n = 13) were recruited for this study as described in detail previously (Darragh et al., 2023). That study investigated within‐subject variability in the circulating metabolome under controlled conditions and whether divergent exercise training backgrounds were associated with alterations in the circulating metabolome assessed in resting samples (Darragh et al., 2023), yet the present study is an entirely separate analysis of those samples focused on small EVs. Based on the recently proposed participant classification framework (McKay et al., 2022), END was comprised of n = 8 tier 3/highly trained athletes and n = 5 tier 4/elite athletes, whereas STR was comprised of n = 9 tier 3/highly trained athletes and n = 4 tier 4/elite athletes.…”

“…Participants arrived at the laboratory on two separate occasions (termed visit 1 and visit 2) under controlled conditions. Participants were provided with standardised meals (30 kcal/kg as 50%/25%/25% for carbohydrate, protein and fat; GourmetFuel, Dublin, Ireland) for consumption on the day before each visit, were asked to abstain from alcohol consumption for at least 24 h, arrived after an overnight fast and only having consumed water that morning and were asked to abstain from exercise for at least 24 h before the visit (Darragh et al., 2023). Participants lay supine for 10 min before a venous blood sample was taken from a superficial forearm vein.…”

“…By comparing resting blood samples from men with divergent exercise training histories, we recently observed that an abundance of 44 metabolites differs between recreationally active, endurance‐trained and strength‐trained participants, which suggests that the circulating metabolome is altered by exercise training (Darragh et al., 2023). Therefore the purpose of this study was to identify whether the abundance of circulating small EVs, and the metabolomic profile of small EVs, was different in resting blood samples taken from these same participants using orthogonal methods of small EV identification and characterisation, while also controlling for confounding factors that can influence signals associated with small EV abundance (i.e.…”

Functional assays reflective of cancer hallmarks in BT‐549 cells are not impacted by media supplemented with exercise‐trained plasma

“…Based on the recently proposed Participant Classification Framework (McKay et al., 2022 ), END comprised n = 8 tier 3/highly trained athletes and n = 5 tier 4/elite athletes, and STR comprised n = 9 tier 3/highly trained athletes and n = 4 tier 4/elite athletes. The phenotypic and performance characteristics of these participants are detailed extensively elsewhere (Darragh et al., 2023 ). Briefly, the STR participants’ recent one repetition maximum (1RM) in the squat exercise was 228 ± 30 kg, and the END participants’ recent 5‐km personal best was 16:30 ± 1:22 min:s. The CON participants were recreationally active (tier 2 of the Participant Classification Framework), but did not engage in any form of structured exercise training and self‐reported being unable to achieve a squat 1RM of >140 kg, or a 5‐km time of < 25:00 min:s. This study received ethical approval from the Research Ethics Committee of Dublin City University (DCUREC/2021/079) and conformed to the standards set by the Declaration of Helsinki , except for registration in a trials database.…”